Recognition of essential purines by the U1A protein

BMC Biochemistry

Table 3 Stability of complexes of wild type U1A protein with SL2 RNA sequences containing A6 modifications.

	WT	A6P	A6c1A	A62AP	A6DAP	A6I	A6G
K_D (M)^a	3 ± 2 × 10^-10	1 × 10^-8c	1.2 × 10^-8d	7 ± 1 × 10^-7	1.1 ± 0.4 × 10^-7	8 ± 2 × 10^-6	3 × 10^-5d
ΔG (kcal/mol)^b	-13.0 ± 0.4	-10.9^d	-10.8^d	-8.4 ± 0.1	-9.5 ± 0.3	-6.9 ± 0.2	-6.2^d
ΔΔG^c		2.1	2.2	4.6	3.5	6.1	6.8

^aK_D values are the average of at least three independent experiments. Standard deviations determined from the independent measurements are reported. ^bΔG is the free energy of association of the complex. ^cΔΔG is the difference between the binding energies of the wild type U1A protein for SL2 RNA containing the indicated base substitution and wild type SL2 RNA. ^d Previously reported in ref. 18.

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